Commit 982134ba6261 ("mm: avoid wrapping vm_pgoff in mremap()") fixedthe case of a expanding mapping causing vm_pgoff wrapping when you usedmremap. But there was another case where we expand mappings hiding inplain sight: the automatic stack expansion.

This fixes that case too.

This one also found by Robert ÅwiÄcki, using his nasty system callfuzzer tool. Good job.